1. Field of Invention
The present invention relates to an electrical device, and more particularly to an electric reciprocating motion device with a spring motor, which is adapted for generating a reciprocating rotational output at a rotary shaft of the motor.
2. Description of Related Arts
The existing electrical devices, such as an electric toothbrush with a vertical type brush head, can be mainly cataloged into the two following types. The first one is that an eccentric wheel is coupled with an output shaft of a motor, wherein when the electric toothbrush is operated he entire toothbrush and its brush head are vibrating in a certain range of amplitude. However, the vibrating amplitude of this type of toothbrush is relatively smaller. Another type of toothbrush is applied an electromagnetic induction principle to generate an electromagnetic vibration, so as to provide the vertical reciprocating motion at the brush head. However, the structure of the second type of toothbrush is complicated, its volume is relatively larger, and the noise from the toothbrush and energy power consumption is higher.
In addition, most of the rotary shafts of conventional motors are outputting a rotatable motion in one single direction. In order to provide a reversible reciprocating motion, an external mechanical conversion device is usually applied to incorporate with the motor, or adapts a stepping motor for controlling purposes. However, it always involves complex structure, large volume, and high manufacturing cost.